"Prosody is the ""music of speech."" Through variations in pitch, timing, loudness and voice quality it communicates grammatical, pragmatic, as well as affective information. The current project will focus on the acoustic cues that are important for the affective aspects of prosody, those which communicate emotion. By parametrically manipulating three acoustic cues, pitch, timing and loudness, in emotional speech samples, this project will investigate the relative importance of each of these cues in communicating basic emotions. In Exp. 1, these cues will be manipulated together to create speech stimuli that are 25%, 50%, 75%, 100%, 125% or 150% ""emotional,"" and adults will choose 1) which emotion they perceive and 2) how intensely that emotion is conveyed. In Exp. 2, the three parameters will be manipulated separately from one another to determine their individual effects on emotion perception. The task will be the same as Exp. 1. In Exp. 3, we will investigate the well-established preference of infants for infant-directed speech (generally positive affect) over adult-directed speech (generally more neutral affect). Pitch has long been thought to be the most important factor in this preference, but that assumption has lately been questioned. This experiment will investigate this, again by separately manipulating the three acoustic characteristics. In Exp. 4, children with high-functioning autism/Asperger syndrome (HFA/AS) or Williams syndrome (WS) and matched typical controls will complete the same task as adults in Exp.1. Emotion recognition deficits are frequently shown in both HFA/AS and WS, but the mechanisms behind these deficits in vocal emotion perception, the point at which the impairment lies, is still unknown. Results from this series of experiments will both provide fundamental knowledge about the means by which we perceive emotions and move toward improving treatments for impairments in recognition of emotion in developmental disbilities."